The Effect of the Water Soluble Fraction of North Sea Crude Oil on the Transport Mechanism of Taurine in Erythrocytes from Flounder, Platichthys Flesus (L.)

Abstract

Flounder erythrocytes has been used as a model to study the effect of petroleum hydrocarbons on amino acid transport systems in cell membranes. The effect of water soluble fraction (WSF) of North Sea crude oil on the transport velocity of taurine into the cells - influx, has been measured using 14-C labled taurine. Two different methods of exposure were performed; flounder were exposed in vivo for 1 month in flow-through aquaria to 0. 1-0.3 ppm WSF, and erythrocytes were collected from un-contaminated fish and exposed in vitro for 20 min - 23 hours, to salt media containing different oil-concentrations (approx. 1 ppb-10 ppm). Taurine influx was inhibited after both exposure methods used, at all concentrations tested and already after 20 min. exposure. Both the sodium dependent and the sodium independent transport mechanisms were affected. The in vivo studies showed that fish in low condition were more vulnerable to the oil-exposure than fish in good condition. The basic regulatory mechanism maintaining a stable cell volume during changes in plasma osmolality was intact in oil-exposed fish. The in vitro studies showed that the negative effect on the transport mechanisms was reversible after washing the oil- exposed cells in un-contaminated salt media. The cell volume was not affected under the performed tests although the taurine transport mechanism which take part in the cell volume regulation was inhibited.